Vaginal specula are commonly known apparatus presently used in the field of diagnostic medicine for purposes of examining the cervix of a female patient. A typical vaginal speculum includes an upper blade member and a lower blade member that are operated upon to open and close by means of an articulation mechanism in order to dilate the vaginal cavity of the patient. According to one version of a vaginal speculum apparatus that is manufactured and sold by Welch Allyn, Inc. of Skaneateles Falls, N.Y., a corded illumination assembly is received within a hollow handle portion of a disposable speculum made from a molded plastic material. The illumination assembly includes a miniature light source, such as a halogen or other miniature incandescent lamp, which is contained within an assembly housing and is tethered by cabling to a dedicated (e.g., AC) power source. The light source is coupled, when received by the hollow handle portion, with the proximal end of a curved light pipe disposed within the lower blade member, the light pipe being formed from a light transmissive material. Light is transmitted from the light source by means of internal reflection along the light pipe to a distal end, the light pipe extending along the interior of the lower blade member. Light is projected from the distal end of the light pipe toward the distal end of the lower blade member to the target (i.e., the cervix), thereby permitting a practitioner to conduct an effective patient examination.
One problem with the herein-described light pipe is that a so-called “hot” spot is developed at the distal light emitting end. The distal light emitting end further produces back reflection of light to the eye of the user along a viewing aperture of the speculum that is formed between the upper and lower blade members at the proximal ends thereof. This back reflection produces considerable amounts of glare, thereby impairing the effectiveness of an examination. In addition, the configuration of the distal end of the current light pipe provides non-uniform light distribution at the target (e.g., the cervix).
Another problem is that the body of the light pipe extends into the lower field of view of the user (e.g., the physician), creating obstruction of the target. In addition, shadowing of external illumination is caused by the distal light pipe end.
A further concern is the amount of plastic material that is used in the lower blade member of the molded disposable speculum, including the material taken up by the light pipe and the hollow handle portion. Excessive plastic material results in extra cost of manufacture. The molding of the lower blade member is further affected in that a stress concentration is created at the distal end of the light pipe, based on its squared discontinuous end, resulting in weak location and potential breakage. Moreover, there is difficulty in molding due to the abrupt change in cross section near the gate.
Yet another problem is that body fluids expelled from examination are often trapped by the distal end of the light pipe, producing a contamination issue as well as impairing the efficiency of examination given the effect on light transmission of a buildup of fluids against the light-emitting surface of the light pipe.
Yet another problem is that the industry has become content with the concept of utilizing a tethered illumination assembly. Though effective and highly useful, there are occasions in which such assemblies make examination impractical to perform such as, for example, instances in which the patient is bed-ridden. In these situations, the corded portion of the speculum apparatus can become an impediment to examining a patient. In addition, the use of corded illumination assemblies requires a non-portable (e.g., AC) power supply to be present in the examination area, making field examinations difficult. Still further, corded assemblies can become tangled or become a source of dirt or other contamination, requiring frequent cleaning between examinations.
Yet still further, the advent of alternative light sources, such as LEDs, provide a means for providing efficient illumination with a longer service life than that of incandescent lamps. Heretofore, the incorporation of such light sources in portable illumination systems for vaginal specula has been discouraged in the field due to inefficiencies in power conversion and illumination output. Provision of these light sources, at least in certain instances is desirable, but presently unavailable for use in such apparatus.